Simplify load test

[wojtek-t]

With migration to CL2 being roughly done, I would like to simplify and evolve load test a bit to:

1. create a service in a bundle with RC
2. that creates a problem that we currently have a service only for half of RCs, but fortunately in new enough releases we can solve that by using the mechanism introduced here: Make kube-proxy service abstraction optional kubernetes#71355
3. switch to using Deployment instead of RC

/assign @krzysied

[wojtek-t]

@kubernetes/sig-scalability-feature-requests

[krzysied]

The problem I see here is that running this simplified load test for older k8s versions will not work. I think we need to split tests into legacy/ head/.
This change will also be required when we switch to new api responsiveness metric.
Wdyt?

• Creating legacy and head directories with copies of test configs ClusterLoader - Copying tests to head/ and legacy/ #450
• Changing scalability jobs config
• Removing all test configs

[wojtek-t]

I'm fine with legacy/ and head/ for other reasons (e.g. responsiveness metric).

But I don't understand why you need it for the purpose of this issue?

[krzysied]

IIUC we want to use kubernetes/kubernetes#71355 which will not be available for older k8s version, right?

[wojtek-t]

Ahh - that's what you meant. Yeah, though given that we only run older releases on 100-node tests, even if that would have no effect, it should still be fine...

[wojtek-t]

Actually, I think that PR that was submitted wasn't exactly what we want.
We should create head/ and legacy/ subdirectories within individual tests, as needed.

Or rather, I would say we should even go one step further:

• create a legacy/ directory (within tests that we need to modify, so probably both actually)
• migrate old branches to use configs from that directory
• leave everything else as is
  Once this is done, we may start modifying the current configs.